Change [] to array() in PHP tutorial

The `[]` syntax (for array creation) works from 5.4 and on, so for
backward compatibility use the `array()` syntax instead.
Prettify table in `API` Object/SetPublishSettings
Add to sessionGUID to Object/SetPublishSettings
Add version compatibility notice to PHP tutorial
Change API so it uses Sphinx Python Domain

Format the `Extensions` as modules and `Actions` as function. This
makes more semantic sense, such that the style is separate from the
semantics.
Style new API format

The changes and additions in the Javascript files are in order to

* Add function names to the sidebar menu
* Change the Python style (`Object.Method()`)
  to CHAOS style (`Object/Method`)
Add style to the `.. seealso::` directive
Add introduction to `API`
Change master branch to `v4`

api.danskkulturarv.dk and api.chaos-systems.com right now run with an
API that looks like `v4` and as they are the main repositories for 
CHAOS data, I think the "current" or "main" should be v4.